Best way to generate Feign Client for JHipster

I have to services and two entities

entity AEnt {}
microservice AEnt with A
entity BEnt {}
microservice BEnt with B

And I want to realize the relation like

relationship OneToOne {
    A{b} to B
}

but programmatically.

So I need JPA + DTO for BEnt in microservice B and only service-layer DTO and service class or service interface with implementation based on feign client (or rest template) in service A.

Is there are the best way to do this? Do I need:

1. Copy BEntDto and Service Interface from B app to A app and implement interface manually?
2. Extract dto POJO and interface into the third library, something like microservices-core?
3. Maybe run service B, download OpenAPI spec, generate spring-client from it?

To clarify my problem:

Service A - Book info service

Service B - for images, ie store book cover

I need to create full info json-response for some book, ie size, color and url in s3 storage from a book. But my API and data-model not stable now, I often change data and do not want to do it manually, but completely automated (jhipster jdl and etc.)